A senior Australian Orthodox rabbi had his glasses ripped from his face during a synagogue altercation with a relative of a prominent advocate for sex abuse victims.

Rabbi Zvi Telsner, the spiritual leader of the Yeshivah Center, which houses the city’s Chabad headquarters, offered festive greetings to Chaim Waks at the end of the Shavuot holiday service on Tuesday night inside Chabad’s main synagogue in Melbourne..

But Waks, 24, whose brother, Manny, has been at loggerheads with Chabad since he first went public in 2011 with claims he was sexually abused when he was at the Chabad-run school in the 1980s, admitted to asking the rabbi: “How dare you f***|ing wish me a good Yom Tov?”

Manny Waks confirmed his brother also admitted throwing Telsner’s glasses on the floor.

Telsner, who was born in New York, declined to comment but confirmed to JTA that the incident happened.

Manny Waks said in a statement: “I have informed Chaim that this type of behavior is completely unacceptable. It makes no difference what an individual has done – in this case the ongoing attacks by Rabbi Telsner and some within his community against my family. The use of violence is never an option and needs to be unequivocally condemned.”

Waks also accuses senior Chabad rabbis of covering up complaints by parents of sexual abuse and even helping alleged perpetrators flee the country, sparking a bitter feud between the family and Chabad officials. He also claims his complaints to Chabad’s then-chief rabbi were ignored.

His father, Zephaniah Waks, claims he has been shunned by his own community and denied rites at Chabad’s main synagogue since the furor erupted in 2011. Chabad officials deny those claims.

Zephaniah Waks claimed he was harassed by another congregant inside the sanctuary the day after the incident between his son and Telsner. He has reported the matter to police.